


Sugar’s Birthday Bash

by Undertale_Writing_Challenges



Category: Undertale (Video Game)
Genre: Birthday Present, Fontcest, Horrorcest - Freeform, Incest, M/M, Mating Cycles/In Heat, Sibling Incest, Teasing, listen, lots of teasing, lowkey oblivious sans, oof, tra la la beware the woman who is bad at tagging, what, yes - Freeform
Language: English
Status: Completed
Published: 2018-08-14
Updated: 2018-08-14
Packaged: 2019-06-27 06:17:27
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,180
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15679689
Author URL: https://archiveofourown.org/users/Undertale_Writing_Challenges/pseuds/Undertale_Writing_Challenges
Summary: It’s Sugar’s birthday and Blood has a whole day of plans for him.Too bad Sugar’s been feeling a little heated lately.HAPPY BIRTHDAY MEGALOTRASH YES MWAH I TRIED <3alternate title: megalotrash’s birthday bash (wink wink)but then technically also megalotrashy’s birthday… bashy.birthday smash more like AMMIRITE





	Sugar’s Birthday Bash

**Author's Note:**

  * For [MeGaLoTrash](https://archiveofourown.org/users/MeGaLoTrash/gifts).



> whOOOO HAPPY FUCKEN BIRTHDAY MEGALO THOUGHT I FORGOT NAH I TOLD YOU I’D DROP YOU SOME SEXY ASS HORRORCEST ON YO SEXY ASS BIRTHDAY SO HERE WE ARE
> 
> you’ve written a lot of gift fics for people. now it’s your turn. sit yo ass down and let me give you a birthday sexgift. it will be so hot you will face the wrath of a thousand nosebleeds and feel vengeance for the amount of panties you’ve ruined. in like, a good way. 
> 
> i dunno, something like that or other. lowkey just happy birthday :3 we love you 
> 
> also i hope you don’t mind me stealing your Dialect For Papyrus in how Everything He Says Is A Title-- i used to make fun of people on games who did that but it’s surprisingly fitting for tale papyruses. no bulk of the FULL CAPS but the intent is there.

“papyrus,” The name is said so reverently against him as he’s gently shaken awake. With a groan and a sleepy sigh, he blearily opens his eyes to see his brother smiling down at him. “happy birthday.”

 

He jolts, sitting up suddenly and almost bowling his brother over… his brother who just called him by his name. His  _ real _ name.  _ Stars _ , it’s been almost a year since anyone’s called him that… not since… “You Called Me Papyrus,” he murmurs softly, yawning around his words and rubbing the sleep from his sockets. He spares a glance to his alarm clock… it was _ early.  _ The sun had just risen and was spilling dully through the window. By Sans standards ( _ Sansdarts _ , so appropriately punned by Blood) it was still the middle of the night.

 

“y’know, to me, it was your name long before it was that cinnabunny’s name,” The other Papyrus had been dubbed many softer nicknames by Blood that were usually tossed around teasingly… but as for him, it was always Sugar, said so adoringly up to him. Adoringly, reverently,  _ lovingly.  _ “and today is  _ your  _ birthday.”

 

“Isn’t It Also Papyrus’ Birthday, Though?” Sugar counters, crossing his arms and feigning a scowl as his brother suddenly and quickly yanks the covers away from him.

 

“eh. nuance,” Blood shrugs him off, sliding back down off the bed and looking over his shoulder at Sugar with a wide grin. “the point is, today is  _ your  _ day, and i’ve got plans for the whole of it… starting with a homemade breakfast.”

 

Blood was shimmying out of the other’s room before he was given even a chance to process his words. “Wait, Brother, Did You Say—”

 

* * *

 

 

By the time Sugar was dressed for the day, (his favorite outfit; a white midriff that rode high and hugged his chest coupled with his soft pink skirt and thigh-high socks) there was a pleasant aroma wafting up the stairs.

 

Following his (lack of) nose he finds his brother in the kitchen putting final touches on a stack of waffles that look like they just came off the iron. But that wasn’t all; the kitchen table was covered in a delectable spread, from pancakes and fresh biscuits to eggs and bacon still steaming.

 

“You… You Cooked All Of This?” He pulls out a chair and sits, knees suddenly weak as he gazes upon the feast in front of him.

 

Blood nods. “of course;” He smiles warmly at Sugar as he fills a plate of a little bit of everything before setting it gently in front of the other. “my bro deserves nothing less than a perfect breakfast on his special day.”

 

Sugar looked down at his heaping helpful of breakfast, letting out a shaky breath as he reached for one of the fluffy biscuits on the side of his plate. The smell was mouthwatering and he couldn’t help but sink his teeth into the flaky biscuit. They tasted just like he remembered, just how he remembered Blood used to make them before… 

 

Well, Blood just hasn’t cooked in a  _ really  _ long time. Sugar didn’t even know that he still knew how… He knew that whenever he mentioned it the other would get uncomfortable, so the fact that his brother made this entire breakfast just for him had his cheeks warming…

 

Actually, it had  _ all  _ of him warming. Just thinking about his brother was already making him feel tingly, but the thought that Blood would put away his own discomfort just to make him happy… His entire body felt heated and it only got worse the more he thought about his brother. 

 

“whatsa matter, sugar?” He jerks at the sudden break in the silence, looking over at his brother who was already digging into his own plateful. “biscuit taste funny? it…  _ has  _ been a while…”

 

“No… They’re Perfect… Just Like I Remember.” He flashes his brother a wide grin before taking another large bite of his biscuit.

 

* * *

 

 

The rest of breakfast went off without a hitch… well, more or less. The odd heated feeling that had overcome Sugar never fully went away but instead had slowly become more manageable. He hoped that once they got outside in the cool autumn air he would cool down… 

 

He was wrong.

 

Blood really did have plans for the entire day. It seemed like they were running around practically the entire town, doing one thing after the next; to others everything they did might have seemed small and trivial, but every single stop they made was something that Sugar  _ loved.  _ Little things that he had started doing since they’d made it to the surface with their counterparts, things that he really enjoyed doing. Blood never really accompanied him, and Sugar didn’t even think he knew he did these things. But his brother shocked him, from taking him to the park to feed the birds to stopping by his favorite sandwich shop for lunch, the day was filled with such simplistic activities that Sugar enjoyed doing almost more than anything. And somehow, every new surprise had his body flaring with the strange heated feeling.

 

At first he’d contemplated telling his brother, but Blood seemed so excited to lead Sugar to every new place, pulling him by the arm and short legs for once taking the lead as he weaved them through the town. He could wait until his birthday was over. After all, he  _ was  _ having fun, despite how uncomfortable the heat was making him. 

 

He’s not sure if he had done a good job hiding it, though. As the day progressed, Blood seemed to be getting oddly more and more tense, grin locked in place and voice a little clipped. It was like he was being affected by the weird heat thing too... Perhaps they were both coming down with something?

 

Nevertheless, he’s pretty sure he’d managed to hold himself together well. It was getting late, nearly dinnertime. They would have to be heading back home soon to eat, and then he could go rest and try to sleep this feeling off. Still, he’d had a lot of fun today, sharing all this time with his brother. He can’t remember the last time they’d both been able to spend the day together, one of them usually always busy with work. He hopes they get another chance to hang out like this-- on a day when he’s  _ not  _ feeling strange.

 

“Thank You, Brother,” he murmurs as they both stand, brushing the sand off his skirt and taking a final breath of the salty air as the last traces of the sunset disappeared beyond the shore. “Today Was Perfect.”

 

“heh. day’s not quite over yet, sugar,” He takes the other by the hand again, leading him away from the beach. “i got one last surprise for ya.” 

 

And he let himself be led, weaved through the streets once again, and he prayed that he could handle whatever this last surprise was, prayed that it would be short and sweet and-- “we’re a little early, our reservation is for 9.”

 

“Reservation…?” Sugar looked ahead, seeing the sign on the building they were heading towards come into view and  _ no.  _ It  _ couldn’t  _ be. The restaurant he’d wanted to go to since they’d made it to the surface,  _ Incontro Riscaldato.  _ Reservations were  _ expensive  _ and so was the food, he hadn’t been able to scrape up the cash to go himself and… And here his brother was, leading him straight towards the entrance and--

 

He froze, the heat searing up suddenly,  _ violently,  _ he felt his knees go weak and he slumped against his brother.

 

“S- _ Sans--” _

  
  


* * *

 

 

Blood nearly lost his balance as Sugar slumped against him heavily. He turned around to find his brother on his knees, face flushed as his grip on his hand tightened and suddenly… the last piece of the puzzle slotted into place.

 

That caramel scent that had followed them around everywhere, the way Sugar seemed so distant, the way  _ he  _ himself could barely  _ think  _ around him. He should have known this would have happened one day or another, especially with how well Sugar’s been adapting to surface life but… He hadn’t expected to be so  _ soon.  _

 

“sugar... are-- are you okay?”

 

“ _ Sans,”  _ Fuck, there he was, saying  _ his  _ name again. It wasn’t making this any easier. “I… I Don’t Know What’s Wrong… I’m Just... So…  _ Hot…”  _

 

“...we need to go home.” His voice sounds hoarse and he winces, desire practically rolling off of him in waves. He hopes Sugar is too oblivious to notice. “can you stand?”

 

And he tries,  _ tries  _ to stand, but he wobbles and leans farther against Blood with a  _ whine.  _ And  _ fuck  _ all he can do is pray to the stars that his self-control doesn’t fail him. “I… I Don’t Think So… Brother, What’s Going On?”

 

He opts not to answer, instead grabbing a tighter hold of Sugar and murmuring “it’s okay, i know a shortcut,” before teleporting them back home with a pop of magic.

 

Normally, Sugar complains when he rips them through space and time, denying motion sickness to instead screech about Blood’s laziness but… He doesn’t think Sugar even realized they teleported and are now in his room… with Blood on top of him…  _ fuck  _ this was not the plan. He needs to move  _ now,  _ go to his room where he can furiously jack off and  _ not  _ take advantage of his heat-drunk brother but--

 

“ _ Sans, I’m So Hot,”  _ his words were a low whine as he squirmed underneath his brother. “ _ Please,  _ Make It Stop.”

 

“...shit, okay listen, sugar, you’re in heat,” He’s not sure if he knows what that means but  _ fuck  _ he hopes he does, he can’t trust himself to stay here any longer he needs to-- 

 

“Help Me… Please…” And then the other’s arms are around him, holding his smaller form tight and preventing his escape… and it would be  _ so  _ easy to just give in… To help his brother… To take the heat away for him… “ _ Sans… Please…” _

 

How could he say no?

 

He presses his teeth to the other’s harshly, not even giving Sugar a chance to react before shoving his tongue into his mouth. He lets out a surprised yelp against Blood’s teeth, but he’s quick to meet his tongue with his own. 

 

Blood felt the taller arch into him, letting out soft, little mewls into his mouth. He felt his higher functions shutting off one by one, and he found it impossible to deny his little brother any longer. He pulled away suddenly leaving Sugar letting out panicked whines and cries for more… “you look so good like this,  _ papyrus.”  _ He leans heavily on his name, a shiver of delight running through him as Sugar’s squirming intensifies at the sound of it. “don’t worry… big brother will take care of you…”

 

He makes his way down the others body, feeling a rush of heat go through his own body when he discovers his  _ innocent,  _ little brother was not wearing any panties. He flipped up Sugar’s skirt and hiked his legs up and over his shoulders, pressing his face directly into the marmalade pussy that was just  _ begging  _ for attention. He was anything but gentle, tongue immediately reaching out and thrusting into that tight, wet heat. “Ohhh!~  _ Stars! _ ” Sugar’s legs tighten around his shoulders and his hands go flying to scrabble at Blood’s head. There’s a careful caution to avoid the gaping hole, frantic hands skating just near but never prodding inside and there’s something primal inside of him that wishes his brother wouldn’t be so gentle with him. “ _ Don’t Stop!! Please Don’t Stop!” _

 

He doesn’t.

 

Instead, he does quite the opposite, moving one of his hands away from Sugar’s beautiful thighs so he could replace his tongue with his fingers, using his mouth to latch onto the soft bead just above his opening. The reaction is instantaneous, liquid rushing and squirting past his fingers as Sugar lets out the most delectable shout of his name. Blood works him through his orgasm with care, drawing it out until he feels the thighs around his shoulders jerking with overstimulation.

 

He pulls back and crawls up the other’s body, cupping his face in his hands and instantly falling in love with the way he looks as he’s coming down from his high. He doesn’t think he’ll ever be able to get this image out of his mind. He presses his teeth to Sugar’s, letting the other taste his own come against his tongue for a brief moment before pulling back to chuckle darkly at him. “still feel hot, love?”

 

“Yes..” He moans out, arching his hips and rubbing his wetness against the crotch of Blood’s pants. “More…  _ Please… _ ”

 

He reaches down and moves the fabric of his shorts just enough to free his length, letting the fat of his cock rest heavily on Sugar’s throbbing pussy, moving slowly and catching his entrance on every thrust but never fully dipping in.

 

_ “Sans,  _ Please…” he whines, rolling his hips and trying to force him inside. “Don’t Tease Me… Please… Give Me  _ More _ ~”

 

_ “anything for my little bro on his birthday.” _

**Author's Note:**

> End notes: if anyone’s wondering how blood made the breakfast so fast he was already making it before he got sugar up so lowkey he was prolly up super fucking early baking biscuits and shit
> 
> also you guys probably already google translated it but incontro riscaldato is Italian for Heated Meeting because I’m uncreative and all that jazz but it sounds like a fancy restaurant does it not?
> 
> Originally, this was supposed to be 2 chapters but uh I procrastinated until the last minute so it’s only one chapter… I hope it was… worth the wait anyways??? Even though this was more or less a surprise??? 
> 
> I still might continue it… maybe...


End file.
